GBAMINEAE. 33 



Eachis of the racemes with the lateral angles broadly winged; first scale of 

 the spikelet usually present. 

 Pedicels terete or nearly so, sparingly if at all hispidulous. 



2. S. hwmifnsum. 

 Pedicels sharply 3-angled, the angles strongly hispidulous. 



3. S. sanguinaUs. 



1. Syntherisma filiforme (L.) Nash. M. p. 76. Dry sandy soil. Sum- 



mer. 



2. Syntherisma humifusum (Pers.) Bydb. Fields and waste places. Sum- 



mer. 

 Philadelphia— (P.). Bucks— (P.). Delaware— (P.). Chester— (P.); -. 

 Lancaster— (P.) . Northampton— (P.) . 



3. Syntherisma sanguinams (L.) Dulac* Crab-grass, Fall-grass. M. p. 



77. Cultivated places, fields, roadsides, etc. Summer. 



9. BEACHIAEIA Ledeb. 



1. Brachiaria digitarioides (Carpenter) Nash. M. p. 77. In water. 

 Summer. 

 Cape May— Peermont (St.), Wildwood (VP.). 



10. ECHINOCHLOA Beauv. 



Sheaths glabrous. 1. E. Crus-galli. 



Sheaths, at least the lower ones, densely papillose-hirsute. 2. E. Walteri. 



1. Echinochloa Crtts-galli (L.) Beauv. Barnyard-grass. M. p. 78. Cul- 



tivated and waste places. Summer. 



2. Echinochloa Walteri (Pursh.) Nash. M. p. 78. In marshes and 



ditches. Late summer. 

 Philadelphia — Philadelphia (P.). 

 New Jersey — Common. 



11. PANICUM L. Panic-grass. 



Spikelets roughened with numerous tubercles, glabrous. 



i , 1. P. verrucosum. 



Spikelets not tuberculate, or if so, the tubercles bearing hairs. 



(A) Basal and culm leaves, similar, usually elongated; spikelets lanceo- 

 late to ovate, commonly the former, acute to acuminate. 

 Lower sheaths round, or but, little flattened, not keeled. 



Culms branched, at least at maturity; no scaly rootstocks nor 

 stolons. 

 Sheaths very pubescent. 



Spikelets lanceolate, 3 mm. long or less. 



Annuals; pedicels not usually more than 2-3 times 

 as long as the spikelets., 

 Culm stout; panicle usually included at the 

 base, its many branches repeatedly divided 

 and bearing numerous spikelets. 



2, P. capillare. 

 Culms slender; panicle exserted, its few 



branches but little divided, and bear- 

 ing comparatively few spikelets. 

 Spikelets 2 mm. long, acute. 



3. P. Philadelphicvm. 



